WINDVANE - self-steer

WINDVANE
SCANMAR INTERNATIONAL
Auto-helm
Installation
and
Operation
Manual
April 2008
Scanmar International
432 South 1st Street
Richmond, California 94804
510-215-2010
Toll-free 888-946-3826
Fax 510-215-5005
email: [email protected]
www.selfsteer.com
AUTO-HELM MANUAL
TABLE OF CONTENTS
Paragraph
1
2
2.1
2.2
2.3
2.4
2.5
3
3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.1.5
3.2
3.3
3.3.1
3.3.2
3.3.3
4
4.1
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.3
4.4
4.5
4.5.1
4.5.2
4.5.3
4.5.4
4.5.5
4.5.6
4.6
4.6.1
4.6.2
4.6.3
4.6.4
5
5.1
5.2
5.3
5.3.1
5.3.3
5.3.4
6
Page
Welcome Aboard ........................................................................................................... 1
Auto-helm Description ................................................................................................... 2
Airvane .................................................................................................................... 3
Flexible Cable Linkage............................................................................................ 4
Rudder .................................................................................................................... 4
Trimtab .................................................................................................................... 5
Rudder Mounting Castings And Hull Brackets........................................................ 5
Installing The Auto-helm ................................................................................................ 5
Preliminaries ........................................................................................................... 5
Important Alignments........................................................................................ 5
Installing Afloat Or Hauled................................................................................ 6
Determining The Proper Height Of Installation ................................................ 6
Tools ................................................................................................................. 6
The Most Important Installation Instruction ...................................................... 6
Fitting The Rudder .................................................................................................. 7
Airvane Mast ........................................................................................................... 8
Preliminaries ..................................................................................................... 8
Installing The Mast Base And Airvane ............................................................. 8
Adjusting Pulley ................................................................................................ 9
Sailing With The Auto-helm Windvane ........................................................................ 10
Becoming A Vane Sailor ....................................................................................... 10
Standard Operating Procedure ............................................................................. 10
Ready The Gear ............................................................................................. 10
Assume The Desired Heading ....................................................................... 10
Balance The Boat ........................................................................................... 10
Trim The Airvane And Engage The Vane Gear ............................................. 10
Your First Sail With The Auto-helm....................................................................... 10
Fine Tuning For Optimum Course Holding........................................................... 11
Balancing For Self-Steering .................................................................................. 12
Problem Boats And Easy Boats ..................................................................... 12
Light Air .......................................................................................................... 12
Running .......................................................................................................... 13
Reaching ........................................................................................................ 14
Hard to Weather ............................................................................................. 16
Give It A Chance ............................................................................................ 16
Useful Hints To Get The Most Out Of Your Vane ................................................. 16
Balance And Trim ........................................................................................... 16
Friction And Binding ....................................................................................... 16
Windvane Alignment....................................................................................... 17
Airvane Adjustment ........................................................................................ 17
Maintenance And Problem Solving ............................................................................. 17
Appearance ........................................................................................................... 17
Regular Maintenance ............................................................................................ 17
Preventing Problems And Damage....................................................................... 18
Collision - Removing The Rudder .................................................................. 18
Locking The Airvane....................................................................................... 18
Hard Weather ................................................................................................. 18
Making Repairs............................................................................................................ 18
Auto-helm Parts list .................................................................................................................. 19
Auto-helm Parts Diagrams ....................................................................................................... 21
1 WELCOME ABOARD
Welcome to the ranks of Auto-helm windvane sailors. We hope you will be as satisfied
with the Auto-helm as we are. The Auto-helm is built to give you years of excellent
performance and to take the kind of punishment the sea delivers.
Many yachtsmen are still unfamiliar with windvane self- steering gear. They view vane
gears as oddities used by single-handed race heroes and circumnavigators. The truth
is that a good vane gear like the Auto-helm is a useful piece of equipment even on
short passages of no more than an hour or so. Once the freedom of sailing with the
Auto-helm has been experienced, this will be fully appreciated.
In order to enjoy the experience of self-steering, the vane gear must, of course, work.
Unfortunately, windvane self- steering is not a push button phenomenon. Knowing how
to sail and how to balance your boat on different points of sail is necessary to get the
most from the gear. Even experienced ocean racing sailors have confessed that
windvane sailing has taug ht them some things they did not know about balancing and
trimming a boat.
This is no excuse for inferior performance. The Auto-helm is built with no corners cut
and the greatest consideration for performance and durability.
This extensive manual is necessary because airvane self- steering requires you learn
about it before you become a perfect operator. Proper installation and p roper operation
are essential, and we hope the number of pages in this manual will not keep you from
reading it.
2 AUTO-HELM DESCRIPTION
The Auto-helm became part of the SCANMAR windvane family in November of 1988. It
has been on the market since the mid-seventies, and has an excellent reputation. It is
totally independent of the boat's primary steering which means that you have no lines
to rig from the windvane to the cockpit. The main rudder is locked and generally used
to balance the boat. One big advantage is that the Auto-helm can be used as an
emergency rudder. The Auto-helm is very easy to operate and to install.
The Auto-helm comes in two halves - the windvane unit and the rudder unit, which can
be totally separated. The connection between the two units is a pair of stainless steel
cables running through teflon tubes. The rudder can be mounted at the correct height
according to the waterline and the air vane mast can be mounted as high as possible to
get clear air. The independent mounting of th e airvane mast permits you to deal with
boats with high freeboard, davits, boomkins and other obstructions. The horizontal axis
airvane is most powerful in the vertical position; but when trimming for sensitivity, it can
be reefed gradually by pulling it down. The horizontal position can be useful if
clearance for the mizzen boom is necessary when jibing or tacking.
The powerful airvane is only asked to turn about 1 sq. ft. of wetted surface of the
trimtab. The flow of the water past the trimtab moves the rudder, which in turn steers
1
Airvane
blades
Airvane
reefing
knob
Locking
pin
Operating
cables
Counterweight
assembly
Tiller arm
assembly
Mast
Operating
cables
Brake
knob
Trimtab control
arm assembly
(yoke)
Mast
base
Trimtab
Rudder
2
the boat. The Auto-helm is capable of steering boats up to approximately 48 feet LOA.
The rudder is a heavy fiberglass shell filled with high density polyurethane closed cell
foam. This makes for a strong rudder which is also buoyant. Due to the buoyancy o f the
rudder, the Auto-helm's true weight is only 32 lb. Shipping weight is approximately 98
lb. The rudder supports are 316L stainless steel, and there is no metal in the water.
The Auto-helm windvane fits most boats, but it is especially suited for boats with
hydraulic or stiff mechanical main steering, a center cockpit, high freeboard, bad
weather or lee helm, davits, or when the skipper absolutely cannot tolerate lines in the
cockpit.
2.1 Airvane
The Auto-helm airvane is made of two lightweight parallel 1/32" thick hard anodized
aluminum plates separated by spacers. It has an aerodynamic shape proven to be very
sensitive in very light air and downwind.
The airvane pivots around a horizontal axis rather than around a vertical axis like the
flag-type vanes seen on some other gear. The horizontally pivoting vane is more
efficient under all circumstances.
The horizontally pivoting vane should be adjusted with its leading edge facing into the
wind when the boat is on the desired heading. The trailing edge, which is the flanged
edge, should be facing away from the apparent wind. When the leading edge is turned
into the wind, the equal wind pressure on either side of the vane blade will keep the
vane upright. If the boat wanders off course, the wind hits only one side of the airvane
causing it to pivot.
Wind
It is important to remember which windvane edge is the leading edge and which is the
trailing one. It is possible to bring the vane upright by turning the back edge into the
wind, but this will produce completely reversed reactions in the vane gear taking the
boat further off course instead of bringing it back to the desired heading.
The airvane is adjusted by rotating the mast with either the tiller (short handle) or the
adjusting pulley located on the mast. The vane is kept in place by tightening the brake
located on the vane base mount.
3
The airvane itself has very little power, even under the best of conditions. To get
maximum performance the Auto-Helm airvane pivots on specially made low friction
teflon bearing surfaces.
The airvane is most sensitive and powerful when set vertically. Ho wever, by moving
the top of the airvane down, you can reef it as the wind increases. The correct positions
for a given boat must be done by trial and error. In general, if the boat starts
oversteering in higher winds or when running, reef the airvane. The vane is also reefed
down if you need to provide clearance to tack or gybe a mizzen boom.
Airvane
upright
Airvane
reefed
The counterweight under the airvane balances the vane. Ideally, it should barely be
able to keep the vane upright when there is no wind. The airvane must not be top
heavy. Without the counterweight keeping the airvane upright, it would not work at all.
2.2 Flexible Cable Linkage
The pivoting of the airvane is transferred via stainless steel wire cable encased in a
teflon tube which is, in turn, encased in a UV-resistant plastic cable cover. The wire
cable is attached to the stainless steel trimtab yoke at the top of the trimtab shaft. This
linkage in the Auto-helm is strong, direct, and the teflon tube gives minimum friction.
The strength coupled with freedom from play and friction in the airvane-to-trimtab
linkage is one important key to the superior performance of the Auto-helm windvane.
When the airvane is in the upright on-course position, the trimtab should be lined up
exactly fore and aft. This adjustment is initially made during the installation of your
Auto-helm. It is accomplished quite easily by adjusting the wire length in the cable
blocks at the airvane.
2.3 Rudder
The semi-balanced Auto-helm rudder is built of fiberglass reinforced polyester resin.
The exterior is gelcoat. The urethane core is composed of a strong, rigid closed cell
urethane.
The near neutral buoyancy of your rudder helps the performance of your boat by
reducing total weight, as well as reducing the moment of inertia in the stern.
4
To avoid marine growth on your Auto-helm, you should paint the underwater parts of
the rudder and trimtab with anti fouling paint. When you "bottom" paint your rudder for
the first time, particular attention should be paid to the paint manufacture's instructions
for preparing the surface. Solvent washing (which should be done) is not enough. The
rudder must be sanded heavily to remove the mold-release wax. The upper portion (out
of the water) should be left unpainted. If the underwater portion is painted with a dark
bottom paint, it should be shielded from the sun when the boat is hauled out of the
water to prevent heat build-up.
The gudgeons and their fasteners are 316L Stainless Steel.
2.4 Trimtab
The trimtab is constructed of the same materials as the rudder. The trimtab has a
vertical shaft running up to the top of the rudder, with a yoke on top for the operating
cables.
2.5 Rudder Mounting Castings And Hull Brackets
The rudder support frame is composed of 1.9" diameter by .065" wall thickness
stainless steel tubing and stainless steel castings. Two UHDPE bearings (at top and
bottom) inside the vertical mounting tube provide a low friction surface for the 1"
stainless steel rudder tube. The rudder tube is held in place by a retaining bolt at the
top. Removal of the retaining bolt and rudder tube allows easy removal of the rudder
from its frame.
The horizontal mounting tubes are fastened to the hull via stainless steel brackets. All
fasteners are 5/16" or 3/8" diameter stainless steel.
The Auto-helm mounting system is universally adaptable to all kinds of stern
configurations. It is easy to install, and once installed is extremely rigid and strong.
3 INSTALLING THE AUTO-HELM
3.1 Preliminaries
3.1.1 Important Alignments
Generally the Auto-Helm is attached to the stern with two upper and two lower
mounting tubes. Some mounts have an additional intermediate mounting tube and/or
diagonal tubes - see the mounting drawing for your boat for details. The mounting tubes
are bolted to the boat by means of universal angle brackets.
The gear MUST be mounted on the centerline of the stern vertically and horizontally.
These alignments are critical, and great care should be taken that the vane gear is
5
neither visibly off center nor tilted forward, aft, or to one side. Often it is helpful to mark the
vertical centerline with a narrow strip of masking tape.
An off-center mount is NOT recommended. When the boat is heeled over, the rudder will be
either too high out of the water, losing steering power, or too low in the water, submerging the
lower mounting tubes.
3.1.2 Installing Afloat Or Hauled
It is generally much easier to install the vane gear with the boat afloat, and with the stern
backed up to a dock. The boat floats true on its lines, and it is far easier to step from the dock
to the boat than to climb a ladder and work off a scaffold. However, the use of safety lines on
tools and parts is recommended to avoid dropping them into the water.
3.1.3 Determining The Proper Height Of Installation
A good way to estimate the proper height of installation is to measure the stern wake while you
are under full power. This is when the boats really squats. The lower mounting brackets should
be three to four inches above this line. Your goal is to avoid burying the mounting hardware
while underway. Mounting the unit too high will result in less than optimum rudder in the water.
Keep in mind that the boat may float differently when loaded for cruising (e.g. full water and
fuel tanks plus supplies). As a rule of thumb, the average cruising boat will ride one inch lower
for every 1,000 pounds of added weight.
3.1.4 Tools
To install an Auto-helm you need:
- A variable-speed electric drill (preferably cordless) with 5/16" and 3/8" bits
- Two 1/2" wrenches
- Adjustable wrench
- Pliers
- Screwdriver
- Mallet (or hammer and wood block)
- Tape measure
- 3/16" Allen wrench (supplied)
- Suitable bedding compound (Boatlife, Sikaflex, etc.)
- Masking tape
- Pencil or marker
3.1.5 The Most Important Installation Instruction
READ THE ENTIRE INSTALLATION PROCEDURE AND BE SURE YOU UNDERSTAND IT
ALL BEFORE STARTING THE JOB. If you have any questions, call or email Scanmar before
you start drilling - we're always ready to help.
6
3.2 Fitting the Rudder
With the stern wake height line marked on the hull, you should back the boat into a slip.
Press the upper and lower mounting tubes into their castings on the rudder post. Use
some lashings to prevent loss of parts. Lift the rudder with a tackle and guide it up
against the transom. Twist and adjust the mounting tube brackets so they lay against
the transom. Mark the location for the mounting brackets.
SPECIAL NOTE FOR INSTALLATIONS WITH AN INTERMEDIATE MOUNTING
TUBE: It's easier to determine where the transom bracket for the intermediate tube is
going to go AFTER the rest of the mounting assembly is mounted. Proceed with the
upper and lower mounting tube assembly as described below. After everything else is
bolted up, insert the intermediate mounting tube into its casting, and raise the casting
until the bracket can be laid flat onto the transom. Then drill all holes and bolt up as
described for the uppers and lowers - see below.
Once you determine the proper height for the upper and lower mounting tubes, you
should remove the rudder from the mounting assembly. This is done by first removing
the retaining bolt that holds the rudder post in place. Next remove the rudder post. This
will allow the rudder to come free from the mounting brackets. The lower UHDPE
bearing is held in place with a set screw to prevent loss when the rudder is removed.
Without the rudder in place, you can easily handle the mounting tubes and brackets.
Again, use a safety line when handling the mounting assembly!
At this point you need to decide where you are going to mount the Auto -helm airvane
and mast unit. If it is mounted on the boat's deck (which normally requires the optional
anodized aluminum toerail bracket), it will have no effect on the rudder mounting tubes.
If, however, you plan to mount it on the upper mounting tubes, you'll have to insure that
the mounting tubes remain long enough (about 9 inches) to provide room for the mast
base. For traditional overhanging transoms which require short upper tubes the mast
base can be mounted on the stern rail or elsewhere.
Hang the mounting tube assembly against the transom. Rotate the mounting tubes in
the castings again, if necessary, to place the mounting brackets over the positioning
marks previously made on the transom. This is also the time to cut the tubes in order to
mount the rudder as close to the hull as possible, if you wish to deviate from the
mounting design shown in your boat's drawing. The tubes are supplied cut to the length
specified in the installation drawing normally will provide the best mount possible.
Contact Scanmar before doing anything permanent!
Re-mark the position of the mounting brackets and the mounting bolt holes. Be
absolutely sure that nothing has shifted while marking the holes!
Drill the bolt holes through the transom using a 3/8" bit. If you have a steel boat, use
drilling lubricant and run the drill at low speed with lots of pressure.
Before you bolt the brackets on you need to be sure that the transom is strong enough
to withstand the forces of an auxiliary rudder. In the case of most fiberglass hulls
backing plates of 1/2" to 3/4" marine plywood behind each mounting bracket are
7
sufficient. If you have a wooden boat or a very thin skinned fiberglass boat, additional
bracing of the transom should be considered.
If you are confident of the strength of the transom, secure the brackets to the hull using
bedding compound and plywood backing plates.
The stainless steel castings on the rudder post have pre-drilled holes for the bolts that
hold the mounting tubes in place. Drill through the castings and mounting tubes with a
5/16" bit. Insert the bolts, put on the washers and nuts, and tighten all up. Use marine
silicon sealer on all bolts and set screws when they are put in for the final time. This
provides a little added insurance to prevent them from vibrating off while underway.
Fit the rudder back onto the mounting assembly. Set the upper gudgeon on top of the
bushing collar protruding from the upper casting, slide the lower gudgeon under the
bushing collar protruding from the lower casting, and insert the inner rudder tube,
locking the rudder in place. Put the cross-bolt through the top of the inner rudder tube.
3.3 Airvane Mast
3.3.1 Preliminaries
Determine where the airvane mast is going to be installed. Be sure the operating cables
can be run to the top of the rudder with easy curves - no sharp bends, which will crimp
the cables.
3.3.2 Installing The Mast Base And Airvane
Note that the airvane mast can be shortened if desired, but plan ahead carefully - take
into account the swing of the airvane both in the vertical and the horizontal 'reefed'
position.
Place the mast assembly on the upper mounting tubes or a base platform bracket on
the stern. Drill through the tubes or bracket (if your bracket is not pre-drilled) and
through bolt with the 5/16" bolts provided.
After the mast is on, bolt the airvane onto the counterweight assembly. See the parts
diagrams for the washer positions.
Bolt the trim tab control arm assembly (the 'yoke') to the top of the trim tab shaft, with
the arms canted AFT. (If it were a swept-wing airplane, it would be 'flying' forward).
Shorten the cable housing, if desired - be sure that the rudder can swing without
binding the cable. Make sure that the cable housing marked PORT (red) goes on the
port side of the rudder. Secure the housings to the fairlead bracket assemblies on the
rudder head. Note that the grommet goes between the stainless steel straps, to prevent
crimping the cables when tightening the bolts.
Clamp
Grommet
Cable
8
Attach the shackles on the operating cables to the yoke on the trimtab shaft. Be sure
that the shackles are not binding and that the cables move smoothly inside their covers.
The upper ends of the cables are held by the cable blocks mounted on the ends of the
counterweight assembly. Insert a cable UP through the hole on the opposite side from
the thumbscrew, then DOWN through the hole nearest the thumbscrew. Leave enough
extra cable to grasp for adjustment. It is easier to adjust the cable tension on both sides
at once. The cables should be set up with minimum slack without binding. If desired,
they can be adjusted for various wind conditions - this will vary from boat to boat.
If the cables are installed incorrectly your Auto -helm will steer backwards. With the
leading edge of the airvane facing forward and the counterweight aft of the mast, the
airvane and trimtab will move in the same direction. When the airvane is moved to the
right, the trimtab should also move to the right.
3.3.3 Adjusting Pulley
Usually the airvane is pointed into the wind by loosening the brake knob and rotating
the mast manually with the tiller arm. If remote operation is required, an endless loop of
1/8" diameter line can be run forward into the cockpit. The line should run around the
adjusting pulley 1-1/2 times, and the forward end of the loop should be kept under
tension with a bungee cord. The adjusting pulley should be as low as possible on the
mast for best operation.
This completes the installation procedure.
9
4 SAILING WITH THE AUTO-HELM WINDVANE
4.1 Becoming A Vane Sailor
The Auto-helm system can usually control a yacht in any wind condition in which it is
possible to sail. One of the most important factors to remember is that each boat will
respond differently to its control system, and may require its own particular adjustments
before accurate self-steering can be established. For instance, after the vane is in
operation, it is sometimes necessary to make slight adjustments to the main rudder or
sails. It is wise to experiment with these relationships and find the best procedures for
your particular yacht.
This part of the Auto-helm manual will make your own introduction a bit speedier. After
giving a standard operating checklist and some hints for your f irst sail with the Autohelm, the procedure of balancing the boat for self -steering is described.
4.2 Standard Operating Procedure
4.2.1 Ready The Gear
If the gear hasn't been used in a while, you should make sure that the cables are at the
correct tension and the trim tab is centered when the airvane is in its upright position.
Loosen the rudder restriction lines if tightened.
4.2.2 Assume The Desired Heading
Go sailing! Get out on the water and pick a course.
4.2.3 Balance The Boat
Balancing the boat for self-steering is crucial to performance. In essence, this involves
choosing a sail combination and trimming the chosen sails to make the boat want to
stay on the desired heading. If a wave or a gust takes the boat off course, the sails
should work to bring the boat back aiding the vane gear instead of fighting it.
4.2.4 Trim The Airvane And Engage The Vane Gear
With the boat sailing on course, rotate the airvane so the leading edge is pointed into
the wind. Pull out the locking pin to allow the airvane to pivot on its horizontal axis. The
Auto-Helm is now sailing the boat .
4.3 Your First Sail With The Auto-Helm
If possible, choose a day with DECENT BREEZE, 10-15 knots or so. Trying the vane
gear out with too much or too little wind will complicate your observation of what the
vane is doing.
10
DO NOT OVER CANVAS. If your boat can be sailed well on a jib alone, you should
SET A JIB ONLY, at least for starters. Not having to deal with a lot of sheets, potentially
gybing booms, and a boat rushing on with her lee rail under will help you concentrate
on the vane gear and making it work on all points of sail. When you are familiar with the
workings and operation of the Auto-Helm, you can add more sail area and drive the
boat faster while your Auto-Helm steers.
START BY SAILING UPWIND without really pinching. Turn the leading edge of the
airvane (the edge facing the mast) into the wind to bring the vane upright and remove
the locking pin.
LET THE BOAT SETTLE DOWN with the self-steering controlling it. Even if the boat is
not going exactly where you intend, give it a couple of minutes to assume a steady
heading. Go aft and observe the way the airvane moves and how this movement
moves the trim-tab and Auto-helm rudder.
MOVE THE AIRVANE SETTING SLIGHTLY WITH THE LEADING EDGE POINTING
FURTHER UPWIND and observe how the boat is taken closer to the wind. Once again
give the boat and the control system time to settle down. Retrim your sail sheet if
necessary.
When you are satisfied that the boat is sailing well on course, change the airvane
setting again with the leading edge pointing further downwind than when you started
out. As the vane makes the boat bear off, retrim your jib sheet and let the boat settle
down on the new course.
Go through all points of sail in a similar fashion. Remember always to a llow the boat
and the vane gear settle down after you have made a change. The most common
mistake is changing too many things too fast. This prevents you from understanding
what is happening and why.
When the yacht is on course, the vane should be more or less straight up. As she goes
off course in either direction, it will respond by tipping to one side or other. In some
instances, the vane system may be fighting a constant weather or lee helm, and will be
cocked to one side during operation. Solutions to this are described in the next section.
4.4 Fine Tuning For Optimum Course-Holding
After you have engaged the vane gear, you should remain at the steering station for a
while to check the self-steering performance.
If the vane gear is constantly working to keep the boat from deviating to one side of the
course only, an adjustment is necessary. The same is true if the boat spends very little
time on the desired heading and more time steering in wide arcs off to each side - a
series of "S"-curves.
You should strive to have the boat stay close to the course line. Deviations should be
small, on BOTH sides of the course line, and be quickly corrected by the vane gear.
This can usually be achieved by fine-trimming which involves adjusting the sails,
11
compensating with the main rudder, and adjusting the vane gear itself.
After the gear has been engaged, you should always try to work it out by SAIL TRIM
FIRST and by adjusting the RUDDER LAST. The objective of balancing should be to
have as neutral a helm as possible. Try to steer the boat with sails alone. This will
insure that the boat keeps on self-steering over a wider range of conditions than would
be true if the boat's rudder was off dead center to compensate for an unbalanced sail
plan.
The boat's main rudder is used to fine trim the boat. Your Auto-helm might be able to
steer the boat with the main rudder free swinging, however, you will probably find that if
you use the main rudder as a giant trimtab, the course will be even straighter. Make
sure to mark the center position on the wheel. If your Auto-helm now seems to work
more on one side than the other, you should help the windvane by moving the steering
wheel an inch or two in the direction that you would steer the boat. Lock the wheel in
this position and study the course a few minutes. Repeat, if necessary, but be aware
that the boat's rudder is very large and powerful and should be moved in small
increments. A rudder that is put too far over will create a lot of drag on the boat speed
and a lot of strain on the boat itself.
4.5 Balancing For Self-Steering
4.5.1 Problem Boats And Easy Boats
Obviously not all boats are the same in terms of the ease with which they can be made
to self-steer.
Factors which make a boat easy for the vane gear to handle are moderate size,
medium displacement, good course stability, moderate response to rudder, little or no
helm on all points of sail, and a sail plan which allows many alternative sail
combinations.
More tuning is required to steer very large, heavy boats, very light displacement boats
with fin keels and spade rudders, and boats with a rig which does not allow many
options for sail combinations and trim.
This does not mean that such boats cannot be steered by the Auto-helm. They do,
however, require more insight and seamanship from the operator.
4.5.2 Light Air
"Does it work in light wind?" This is a standard question posed to anyone involved with
windvanes. Obviously, since the vane gear takes its signals from the wind and its
power from the boat's movement though the water, there has to be wind and the boat
has to move for the vane gear to work.
How little it can blow and how slow the boat can travel with the gear still functioning
depends to a great extent on the boat itself, on the skill of the operator, and on the point
of sail.
12
If the boat is very large, it will generally take a larger rudder to steer the boat. The Autohelm will normally steer boats up to 48 feet LOA. If the boat is much larger, the size of
the Auto-helm's rudder might be too small to control the boat in heavy wind. Light air
performance can be vastly improved by balancing and fine tuning. In general, the gear
will do a better job in light airs on a small or moderate size boat and will remain
functional down to about one knot of boat speed with the corresponding wind strength.
However, a good sailor, balancing his boat properly, can make the vane gear steer a
large yacht in surprisingly light conditions.
In general, the Auto-helm auxiliary rudder system works very well in light winds, slow
boat speeds and often exceeds the light air performance of vanes using other selfsteering principles.
4.5.3 Running
"Does it work downwind?" This question is more common than the one about light
winds.
The problem with self-steering when sailing downwind is that you are moving in the
same direction as the wind. Consequently, THE WIND VELOCITY AVAILABLE TO
THE AIRVANE FOR CORRECT SIGNALS IS DECREASED BY THE SPEED OF THE
BOAT.
While downwind sailing using main and jib it is generally more efficient to fall off the
wind to either side and make long boards, gibing across the wind from time to time,
than to attempt to sail dead downwind.
It should also be noted that the auxiliary rudder will give the boat directional stability
since it is mounted further aft than the main rudder, and this will help downwind
performance.
THE FIRST AND FOREMOST RULE WHEN SAILING DOWNWIND IS USING THE
RIGHT SAILS AND THE RIGHT AMOUNT OF SAIL.
Before the advent of mechanical vane gear, boats were sailed around the world selfsteering downwind in the trades by use of twin head sails on poles. The trick to that is
to sheet the twins a little bit looser than you would for maximum efficiency alone. If the
boat wants to round up, the leeward sail starts spilling wind. The pressure from the
windward sail gradually increases, acting like a giant finger gently nudging the boat
back on course again until both sails are drawing equally.
If you are going to do a lot of downwind cruising, it might be worthwhile to set the boat
up for twin head sails. Combined with the Auto-helm this rig gives excellent selfsteering even on problem boats. It is efficient as well as being very safe and easy to
manage. The only disadvantage is that the boat rolls more than when the main is used.
IF THE MAIN IS CARRIED, THERE SHOULD ALWAYS BE A FORESAIL POLED
OUT ON THE OPPOSITE SIDE TO COUNTERACT THE MAIN. Although this set-up
could not be used for self-steering by itself, it will be an adequate sail combination for
self-steering on almost any yacht using the Auto-helm.
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If you have to drastically reduce sail, take the main down and leave the poled-out jib
hoisted. Although the pressure from a single jib is on one side of the yacht, it is
concentrated at the bow providing better balance and letting the vane gear handle the
boat with relative ease.
Assume that only the main is carried. If the wind is fresh, steering will be like walking a
tight rope. A very attentive helmsman may be able to keep the boat on course by
instantly countering every move away from the course line. The choice of sail makes
the boat increasingly unbalanced as it deviates from the desired heading. Once off
course, the boat gets out of hand. Even full rudder will not keep the boat from rounding
up or gibing once the process has begun. The pressure from the wind is concentrated
behind the mast making the boat want to point into the wind as soon as it gets a little bit
off its precarious equilibrium of sailing more or less dead downwind.
The situation can be likened to moving a cart by pushing it from behind with a stick
(mainsail only) versus pulling it from ahead with a string (jib or twin jibs). It is practically
impossible to keep the cart going where you want it to go with the stick, especially if
any kind of speed is involved. A cart will follow n icely when we pull it from ahead.
The spinnaker is set ahead of the mast and gives good balance as long as nothing
goes wrong. The trouble is that a lot of things can go wrong. The tremendous power of
the spinnaker makes the boat move faster downwind and consequently magnifies the
problem of the weakness in the vane's signals. Since the sail is not hanked onto any
controlling stay or track, it will continue to exert pressure long after a poled-out foresail
would spill its wind. Because of the size of the sail, this pressure can be enormous and
completely overpower the boat's rudder, as anyone knows who has experienced a
spinnaker broach. Therefore, the spinnaker should be used with caution with a
mechanical vane gear.
Summing up: DOWNWIND SAILS AT THE BOW GIVE THE BEST BALANCE AND
SELF-STEERING. IF POSSIBLE, THESE SHOULD BE POLED OUT ON EACH SIDE
OF THE HULL. WHEN THE MAIN IS USED, IT SHOULD ALWAYS BE
COUNTERBALANCED BY A POLED-OUT FORESAIL ON THE OPPOSITE SIDE.
OVER CANVASSING SHOULD BE AVOIDED, ESPECIALLY USING A SPINNAKER
IN HARD WEATHER WHEN IT CAN EASILY LEAD TO BROACHING.
4.5.4 Reaching
We are seldom asked whether the Auto-helm works well on a reach. In fact, reaching
can be harder for the vane gear than other points of sail. While a boat can be made to
steer downwind as well as upwind by itself, achieving this can be much more difficult on
a reach in gusty weather. With a sloop rig there are few options for using sails well fore
and aft to create pressures which make the boat return to the desired heading after it
has swung off course.
With a two-masted rig, especially when the boat has a bowsprit, the mizzen and jib can
be worked to bring the boat back on course when it bears off or starts going to weather.
Even so, this is tricky to do and normally takes some experimenting.
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CONSEQUENTLY, THE VANE GEAR IS MOST NEEDED WHEN REACHING.
However, faulty sail trim can over-power the gear, and it is necessary to understand
how to create the best possible balance. The greatest problem is keeping the yacht
from rounding up when the wind increases in strength.
Twin head sails or main and a poled-out jib can be carried to about 34-40 degrees
away from straight downwind and will provide the best self-steering as long as they can
be kept up. After that the windward pole must come down.
Again, using the main alone is not the way to go. Although you can try to compensate
for the greater weather helm with the rudder before you engage the vane gear, any
increase or decrease in wind strength is likely to change the balance. Once more, you
must strive to balance the boat with the sails first and not use the rudder to compensate
for a significant lack of balance. The rudder should be used for fine tuning after the boat
has been set up to sail on course as much as possible by itself.
If only one sail is used, a head sail should be the choice. However, using a head sail on
a reach does not necessarily to push the bow downwind unless it is hoisted very far out
on a long bowsprit.
When the wind increases, many boats will experience increased weather h elm even
with only the head sail set. However, this weather helm is very mild compared to what
the mainsail would induce under similar circumstances, and the vane gear can easily
hold the boat on course.
When the main and head sail are used, both sails may work to bring the bow to
weather. To limit weather helm, as well as great increases in weather helm during a
gust, each sail, but especially the main, should be SHEETED MUCH LOOSER than
you would do in a racing situation. This will slow the boat an almost unnoticeable bit.
The effect is to make the sails spill their wind at a much earlier point when the boat
wants to round up. The weather helm decreases, and the vane gear is capable of
pulling the yacht back on course.
If you continue to have problems, reduce sail area, especially the main, and continue to
release more sheet even though the leeches may flutter a bit.
When the wind significantly drops, the boat will want to bear off downwind especially if
the main rudder has been used to compensate for a lot of weather helm. This is one of
the chief reasons why the rudder should not be a primary factor in balancing the boat.
In this case, carrying the main is actually helpful. As the boat veers off, the main will
cover the head sail(s) and catch all the wind. This will move the pressure behind the
mast and make the boat want to round up again.
SUCCESSFUL SELF-STEERING ON A REACH IS ACHIEVED BY AVOIDING
EXCESSIVE CANVAS, RELYING PRIMARILY ON THE HEAD SAILS FOR POWER,
SHEETING THE SAILS LOOSELY, AND USING SAIL TRIM RATHER THAN THE
MAIN RUDDER FOR BALANCING THE YACHT.
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4.5.5 Hard To Weather
Most yachts can easily be made to self-steer when hard on the wind without using the
vane gear. Consequently, the vane will have little problem keeping the yacht on course.
Because the movement is towards the wind, the velocity of the wind working the
airvane sensor increases by the speed of the boat. The vane's signals will be true and
strong.
THE BEST PERFORMANCE WILL BE GUARANTEED BY NOT KEEPING TOO
MUCH SAIL AREA AND BY NOT SHEETING THE SAILS TOO HARD. Over
canvassing and over sheeting will only heel the boat unnecessarily, inducing great
weather helm which may become difficult for the vane to control in a gust.
4.5.6 Give It A Chance
Armed with these hints on balancing the boat on different points of sail, you should
experience no difficulty in making the vane gear steer your boat. After you have used
the Auto-helm a while, it will steer even better, and you probably will have learned a
thing or two about sailing and balancing your boat. Give everything a chance to work
and remember that some learning is necessary to get the most from your vane.
4.6 Useful Hints To Get The Most Out Of Your Vane
After you have set up the vane gear to steer your boat, you should remain in the cockpit
for a couple of minutes observing the behavior of the yacht.
The boat should remain on the desired heading, deviations should be small and quickly
corrected, and the vane gear should not be fighting to keep the boat from wandering off
on one side of the course line.
4.6.1 Balance And Trim
If the boat has a persistent tendency to luff or bear off, it is not properly balanced. Sails
have to be either sheeted in or out, reduced, or changed completely. The goal is to get
the boat to sail as close to the desired heading by itself, and have the windvane,
autopilot or helmsman do only minor corrections. USUALLY, RELEASING THE MAIN
SHEET A BIT WORKS WONDERS IN TAMING TENDENCIES TO ROUND UP.
Start your windvane steering with your boat's rudder locked on boat centerline, and do
as much of your course correction as possible with sail trim. Final minor adjustments
can be made by using the boat's rudder as a trimtab, but remember t hat if you trim the
boat using mainly the boat's rudder all will be well as long as the wind is constant - as
soon as the wind speed changes, though, main rudder will take over and the boat will
round up or fall off course.
4.6.2 Friction And Binding
Friction that interferes with the airvane's ability to move the trimtab is a deadly enemy
of light air performance. Friction result from incorrectly led cables to the trimtab. The
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most common problem is overtightening the trimtab cables. They should be somewhat
slack in light air, and the wires should move freely through their sheaths. The airvane
should swing easily from side to side. The Auto-helm rudder and trimtab should also be
checked periodically for binding - both should move freely.
4.6.3 WIndvane Alignment
Check periodically to be sure that the airvane is dead upright when the trimtab is in line
with the rudder centerline.
4.6.4 Airvane Adjustment
A common mistake is reversing the airvane when preparing to selfsteer. The airvane's
counterweight should be moved to the lee side of the airvane mast so the straight
edges of the airvane blades are into the wind. Under most conditions the airvane will be
set up vertically. In strong winds the airvane should be reefed down to about 45
degrees. Experiment to see what's best for your boat.
5 MAINTENANCE AND PROBLEM SOLVING
5.1 Appearance
The Auto-helm is made of hard black anodized aluminum and 316L stainless steel.
After fabrication, the individual stainless parts are electropolished in a chemical bath to
remove impurities from the surface and welds of the metal. The last step is the
assembly of the individual parts to make a finished vane gear.
A periodic fresh-water washdown of the gear to rinse off the salt and airborne grime is
recommended. An occasional application of metal polish on th e stainless parts will
keep them bright and shiny.
5.2 Regular Maintenance
The cables running from the airvane to trimtab are the hardest working part of the Autohelm vane gear. Inspect them frequently and readjust as needed. Do not over tighten
them. They should be slightly slack when correctly adjusted.
The Auto-helm bearings and bushings are made from materials that work better with
water on them. Maintenance consists of hosing the gear with fresh water when you
have the opportunity. Take care to flush all places that have bearings to clean out salt
deposits. Regular rain often takes care of this. Do not use oil.
Vibration when under power can occur on some boats. You should therefore check all
fastenings from time to time. Make sure that nuts and bolts are tight. Vibration cannot
be predicted for any given boat since there are too may variables - prop size and speed
as well as hull configuration are just a few. Monitor the characteristics of your boat and
reduce speed if necessary.
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5.3 Preventing Problems And Damage
5.3.1 Collision -Removing The Rudder
As the rudder is mounted outboard of the hull, it is vulnerable to collision. Unfortunately,
vanes sometimes get damaged by being run into by other less than expert skippers.
This can happen in a marina as well as in an anchorage. Even a bump may do a lot of
damage when it is executed by a yacht weighing several tons.
Be aware of the danger to your vane gear from collision. If possible, berth your boat
with the stern in. Be ready to fend off in crowded situations. Plan your own maneuvers
with the vane gear in mind.
If you are not using the vane gear f or a long period of time, or if there is a serious
possibility that the rudder may be damaged, you should remove the rudder.
5.3.3 Locking The Airvane
When you have finished sailing with the Auto-helm, lock the airvane by inserting the
3/8" fastpin in the hole through the counterweight. This will prolong the life of the
square airvane bearings. By bringing the airvane down to a horizontal position, the wind
will have less pressure on the airvane.
5.3.4 Hard Weather
Hard winds and fast speeds make the Auto-helm very powerful. People have reported
using the gear in extreme storm conditions. Your need to take over would be when the
boat is threatened by dangerous waves. The Auto-helm cannot see a freak wave and in
very big seas there can actually be a lack of wind in the trough between two waves
which would interfere with the steering ability of any windvane.
6 MAKING REPAIRS
The sea punishes everything on a boat. The windvane is possibly the hardest working
equipment of all on a cruising sailboat. Unfortunately, it cannot be engineered with
mammoth dimensions because this would interfere with its ability to steer in anything
but a hurricane.
The construction of the Auto-helm combines great strength with the necessary
lightness to make the gear efficient in all conditions. We strongly recommend periodic
inspections that can correct problems before they become severe. Regular hand tools
are most often all that is needed to make repairs. The gear really is logical and easy to
understand.
The parts lists and diagrams beginning on the next page will help in disassembling and
repairing your Auto-Helm.
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AUTO-HELM PARTS LIST
Airvane
V1.1
Airvane Blade, Right
V1.2
Airvane Blade, Left
V2
Airvane Spacer Tube
V3
Aluminum Spacer Bolt
V3.1
Airvane Reefing Knob
V4
Aluminum Lock Nut
V5
Nylon Washer
V6
Counterweight Assembly
V6.4
Counterweight Bushing
V9
Cable Block Thumbscrew
V13
Cable Block Assembly
V16
Counterweight Bolt
Rudder And Trim Tab
R1
Rudder
R2
Trim Tab
R3
Upper Rudder Gudgeon
R4
Lower Rudder Gudgeon
R5
Trim Tab Gudgeon
R6
Trim Tab Gudgeon Assembly
R7
Fairlead Bracket Assembly
R8
Trim Tab Control Arm Assembly
R9
Trim Tab Bushing
R10
Rudder Bushing
R12
Outer Rudder Tube
R13
Inner Rudder Tube
R16
Rudder Centering Line
R16.1 Ruder Centering Eye Assembly
Mast And Base
B1
Base
B2
Mast
B3
Mast Bushing
B4
Mast Bushing Spring Pin
B6
Locking Pin
B6.1
Locking Pin Lanyard
B7
Cotter Ring
B8
Standard Cable Set
(one pair, 7-foot wire length)
B8.1
S.S. Cable (sold per foot
for custom cable sets)
B8.2
Inner Teflon Tubing (sold per foot
for custom cable sets)
B8.3
Outer Vinyl Tubing (sold per foot
for custom cable sets)
B8.5
Trim Tab Shackle
B9
Cable Clamp Assembly
B10
Brake Pad
B11
Brake Knob
B12
Brake Plate
B13
Tiller Ring
B14
Tiller Arm Assembly
B15
Tiller Arm Set Screw
B16
Tiller Limitation Bolt Assembly
B18
Tiller Limitation Lanyard
B19
Adjusting Pulley
Mounting Components
T1
Mounting Tubes (sold by the inch)
T2
Single Stainless Steel Casting,
with setscrew
T3
Double Stainless Steel Casting,
with setscrew
T4
Hull Mounting Bracket ('L'-bracket,
2007 and earlier)
T6
Rail Mounting Bracket For Mast
T7
Mounting Tube/'L'-Bracket Bolt,
Lockwasher, Nut & Compression
Tube
T8
Hull Mounting Bracket ('U'-bracket,
2008 on)
(See next page for Misc. Hardware)
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AUTO-HELM PARTS LIST (continued)
Misc. Hardware (all stainless steel unless
otherwise noted. F-numbers are Fasco part
numbers)
#10-32 x 1" pan-head bolt, F820
#10-32 nut, F1308
#10-24 x 3/4" pan-head bolt, F809
#10-24 nut, F1307
#10 washer, F1397
#10 lockwasher, F1418
1/4"-20 x 3/4" bolt, F54
1/4"-20 x 1-1/2" bolt, F58
1/4"-20 x 2-1/2" bolt, F62
1/4"-20 x 3-1/2" bolt, F66
1/4"-20 x 4" bolt, F67
1/4"-20 nut, F1310
1/4" washer, F1970
1/4" washer, 11/16" O.D., F1399
1/4" lockwasher, F1420
1/4" nylon washer, F2981
5/16" fender washer, F1431
5/16" lockwasher, F31421
3/8"-16 x 3-1/2" bolt, F30108
38"-16 x 5" bolt, F30111
3/8"-16 nut, F1312
38" washer, F1401
38" lockwasher, F1422
1/2"-20 thin nut, F2882
1/2"-20 thin lock nut, F3357
1/2" thin washer, F3561
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